Network data collection method from application function device for network data analytic function

ABSTRACT

A network data collection method from application function device for network data analytic function is disclosed. The network data collection method includes transmitting a Naf_EventExposure_Subscribe message for a subscription of an event into an application function (AF) device; and receiving a Naf_EventExposure_Notify message from the AF device when the NWDAF subscribes the event.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of Korean Patent Application No.10-2019-0038720, filed on Apr. 2, 2019, No. 10-2019-0053074, filed onMay 7, 2019, No. 10-2019-0053317, filed on May 7, 2019, and No.10-2019-0161022 filed on Dec. 5, 2019, in the Korean IntellectualProperty Office, the disclosure of which is incorporated herein byreference.

BACKGROUND 1. Field

One or more example embodiments relate to a network data collectionmethod from application function device for network data analyticfunction.

2. Description of Related Art

Various data is generated in the network. In order to analyze varioussituations of such a network, it is necessary to collect network data.Various settings are necessary for the collection of such network data.

In particular, since parameters set when collecting network data aredetermined at the time of collecting network data, they may not bechanged once determined. Thus, a method for setting parameters whencollecting network data is required.

SUMMARY

According to an aspect, there is provided a network data collectingmethod performed by a network exposure function (NEF) device,comprising: transmitting a Nnrf_NFManagement_NFUpdate_request messagefor update registration information into a network repository function(NRF) device; receiving a Nnrf_NFManagement_NFUpdate_response messagefrom the NRF device; receiving a Nnef_EventExposure_Subscribe messagefrom a network data analytic function (NWDAF) device; transmitting aNaf_EventExposure_Subscribe message into an application function (AF)device; receiving a Naf_EventExposure_Notify message from the AF device;transmitting a Nnef_EventExposure_Notify message into the NWDAF device.

The Naf_EventExposure_Subscribe message comprise: (i) an input includingTarget of Event Reporting, external UE ID, External Group Identifier, orindication that any UE is targeted, Event ID, Notification TargetAddress with Notification Correlation ID), Event Reporting Informationand Expiry time, (ii) an output including Operation execution resultindication, and Subscription Correlation, when the subscription isaccepted.

The NRF device stores NEF registration information including availabledata to be collected from the AF device.

The Nnef_EventExposure_Subscribe message comprise: (i) an inputincluding Event ID, Target of Event Reporting, GPSI, External GroupIdentifier, Event Reporting Information, or Notification Target Addresswith Notification Correlation ID, and (ii) an output includingSubscription Correlation ID, or Expiry time.

The method further comprises transmitting aNaf_EventExposure_Unsubscribe message into the AF device. TheNaf_EventExposure_Unsubscribe comprises: (i) an input includingSubscription Correlation ID, and (ii) an output including Operationexecution result indication.

The Naf_EventExposure_Notify message comprises: (i) an input includingNotification Correlation Information, Event ID, corresponding UEexternal UE ID, External Group Identifier, indication of any UE or timestamp.

The Nnef_EventExposure_Notify message comprises: (i) an input includingEvent ID, Notification Correlation Information or time stamp, and (ii)an output including Operation execution result indication.

The AF device invokes the Naf_EventExposure_Notify message into the NEFdevice, when the NEF device subscribes to data in the AF device.

The NEF device invokes the Nnef_EventExposure_Notify message into theNWDAF device, when the NEF device receives a notification from the AFdevice.

The NWDAF device invokes the Nnrf_NFDiscovery_Request_request message,when the NWDAF needs to discovery an available data from the AF deviceand the appropriated NEF device to collect the available data.

According to an aspect, there is provided a network data collectingmethod performed by a network data analytic function (NWDAF) device. Themethod comprises transmitting a Naf_EventExposure_Subscribe message fora subscription of an event into an application function (AF) device; andreceiving a Naf_EventExposure_Notify message from the AF device when theNWDAF subscribes the event.

The Naf_EventExposure_Subscribe message comprises: (i) an inputincluding Target of Event Reporting, external UE ID, External GroupIdentifier, or indication that any UE is targeted, Event ID,Notification Target Address with Notification Correlation ID), EventReporting Information and Expiry time, (ii) an output includingOperation execution result indication, and Subscription Correlation,when the subscription is accepted.

The Naf_EventExposure_Notify message comprises: (i) an input includingNotification Correlation Information, Event ID, corresponding UEexternal UE ID, External Group Identifier, indication of any UE or timestamp.

The method further comprises transmitting aNaf_EventExposure_Unsubscribe message into the AF device. TheNaf_EventExposure_Unsubscribe comprises: (i) an input includingSubscription Correlation ID, and (ii) an output including Operationexecution result indication.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects, features, and advantages of the inventionwill become apparent and more readily appreciated from the followingdescription of example embodiments, taken in conjunction with theaccompanying drawings of which:

FIG. 1 is a diagram illustrating a relationship between NWDAF device andthe NF device according to an example embodiment;

FIG. 2 is a diagram illustrating a procedure for collecting data from NFdevice according to an example embodiment; and

FIG. 3 is a flowchart illustrating a procedure for collecting data fromAF device via NEF device according to an example embodiment.

FIG. 4 is a flowchart illustrating a procedure for collecting data fromOAM device according to an example embodiment.

DETAILED DESCRIPTION

Hereinafter, example embodiments will be described in detail withreference to the accompanying drawings. The scope of the right, however,should not be construed as limited to the example embodiments set forthherein. Like reference numerals in the drawings refer to like elementsthroughout the present disclosure.

Various modifications may be made to the example embodiments. Here, theexamples are not construed as limited to the disclosure and should beunderstood to include all changes, equivalents, and replacements withinthe idea and the technical scope of the disclosure.

Although terms of “first,” “second,” and the like are used to explainvarious components, the components are not limited to such terms. Theseterms are used only to distinguish one component from another component.For example, a first component may be referred to as a second component,or similarly, the second component may be referred to as the firstcomponent within the scope of the present disclosure.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms are intended to include the plural forms as well, unlessthe context clearly indicates otherwise. It will be further understoodthat the terms “comprise” and/or “comprising,” when used in thisspecification, specify the presence of stated features, integers, steps,operations, elements, components or a combination thereof, but do notpreclude the presence or addition of one or more other features,integers, steps, operations, elements, components, and/or groupsthereof.

Unless otherwise defined herein, all terms used herein includingtechnical or scientific terms have the same meanings as those generallyunderstood by one of ordinary skill in the art. Terms defined indictionaries generally used should be construed to have meaningsmatching contextual meanings in the related art and are not to beconstrued as an ideal or excessively formal meaning unless otherwisedefined herein.

Regarding the reference numerals assigned to the elements in thedrawings, it should be noted that the same elements will be designatedby the same reference numerals, wherever possible, even though they areshown in different drawings. Also, in the description of exampleembodiments, detailed description of well-known related structures orfunctions will be omitted when it is deemed that such description willcause ambiguous interpretation of the present disclosure.

Hereinafter, the example embodiments will be described in detail withreference to the accompanying drawings. The full name of a word used inthe present invention is as follows. And, the term AMF, AF, NEF, NRF,PCF, UDM, NWDAF, CHF, NF, and SMF may be represented as device.

-   -   5GC: 5G Core Network    -   AF: Application Function    -   AMF: Access and Mobility Management Function    -   AUSF: Authentication Server Function    -   CHF: Charging Function    -   FQDN: Fully Qualified Domain Name    -   GPSI: Generic Public Subscription Identifier    -   NEF: Network Exposure Function    -   NF: Network Function    -   NRF: Network Repository Function    -   NWDAF: Network Data Analytics Function    -   PCF: Policy Control Function    -   PDU: Protocol Data Unit    -   SMF: Session Management Function    -   S-NSSAI: Single Network Slice Selection Assistance Information    -   SUPI: Subscription Permanent Identifier    -   UDM: Unified Data Management    -   UDR: Unified Data Repository

The NWDAF is part of the architecture and uses the mechanisms andinterfaces specified for 5GC and OAM.

The NWDAF interacts with different entities for different purposes.

-   -   Data collection based on event subscription, provided by AMF,        SMF, PCF, UDM, AF (directly or via NEF), and OAM;    -   Retrieval of information from data repositories (e.g. UDR via        UDM for subscriber-related information);    -   Retrieval of information about NFs (e.g. NRF for NF-related        information, and NSSF for slice-related information);    -   On demand provision of analytics to consumers.

A single instance or multiple instances of NWDAF may be deployed in aPLMN. In case multiple NWDAF instances are deployed, the architecturesupports deploying the NWDAF as a central NF, as a collection ofdistributed NFs, or as a combination of both.

-   -   When multiple NWDAFs exist, not all of them need to be able to        provide the same type of analytics results, i.e., some of them        may be specialized in providing certain types of analytics. An        Analytics ID information element is used to identify the type of        supported analytics that NWDAF may generate.

NWDAF instance(s) may be collocated with a 5GS NF.

FIG. 1 is a diagram illustrating a relationship between NWDAF device andthe NF device according to an example embodiment;

<Non-Roaming Architecture>

The 5G System architecture allows NWDAF to collect data from any NEF.The NWDAF belongs to the same PLMN where the network function thatnotifies the data is located. The Nnf interface is defined for the NWDAFto request subscription to data delivery for a particular context, tomaycel subscription to data delivery and to request a specific report ofdata for a particular context. The 5G System architecture allows NWDAFto retrieve the management data from OAM by invoking the existing OAMservices.

<Network Data Analytics Functional Description>

The NWDAF (Network Data Analytics Function) provides analytics to 5GCNFs, and OAM. Analytics information are either statistical informationof the past events, or predictive information. Different NWDAF instancesmay be present in the 5GC, with possible specializations per categoriesof analytics. The capabilities of a NWDAF instance are described in theNWDAF profile stored in the NRF.

In order to support NFs that are consumers of analytics with thediscovery of a NWDAF instance that is able to provide some specific typeof analytics, each NWDAF instance should provide the list of AnalyticsID(s) that it supports when registering to the NRF, in addition to otherNRF registration elements of the NF profile. Other NFs requiring thediscovery of an NWDAF instance that provides support for some specifictype of analytics may query the NRF and include the Analytics ID(s) thatidentifies the desired type of analytics for that purpose.

The consumers i.e. 5GC NFs and OAM decide how to use the data analyticsprovided by NWDAF.

The interactions between 5GC NF(s) and the NWDAF take place within aPLMN.

The NWDAF has no knowledge about NF application logic. The NWDAF may usesubscription data but only for statistical purpose.

<NWDAF Discovery and Selection>

The NWDAF service consumer selects an NWDAF that supports requestedanalytics information by using the NWDAF discovery principles.

<Network Data Analytics Function (NWDAF)>

NWDAF represents operator managed network analytics logical function.The NWDAF includes the following functionality:

-   -   Support data collection from NFs and AFs;    -   Support data collection from OAM;    -   NWDAF service registration and metadata exposure to NFs/AFs;    -   Support analytics information provisioning to NFs, AF.

<NWDAF Discovery and Selection>

Multiple instances of NWDAF may be deployed in a network. The serviceconsumer NFs may utilize the NRF to discovery NWDAF instance(s) unlessNWDAF information is available by other means, e.g. locally configuredon service consumer NFs. The NWDAF selection function in serviceconsumer NFs selects an NWDAF instance based on the available NWDAFinstances. The following factors may be considered by the serviceconsumer NF for NWDAF selection:

-   -   S-NSSAI.    -   Analytics ID(s).    -   NWDAF Serving Area information, i.e. list of TAIs related to        analytics generated by a NWDAF.

<Nef Device>

-   -   Exposure of analytics:        -   NWDAF analytics may be securely exposed by NEF for external            party.    -   Retrieval of data from external party by NWDAF:

Data provided by the external party may be collected by NWDAF via NEFfor analytics generation purpose. NEF handles and forwards requests andnotifications between NWDAF and AF.

<NEF Discovery>

The service consumer NFs may utilize the NRF to discover NEF instance(s)unless NEF information is available by other means, e.g. locallyconfigured in service consumer NFs. The NRF provides NF profile(s) ofNEF instance(s) to the service consumer NFs. The NEF discovery andselection procedures are intended to be applied by service consumer NFsdeployed within the operator's domain. The following factors may beconsidered for NEF selection:

-   -   S-NSSAI(s).    -   Event ID(s) supported by.    -   AF Instance ID, Application ID.    -   External Identifier, External Group Identifier, or domain name

<Network Exposure>

The network capability exposure comprises

-   -   Exposure of network events externally as well as internally        towards core network NFs;    -   Exposure of provisioning capability towards external functions;    -   Exposure of policy and charging capabilities towards external        functions;    -   Exposure of core network internal capabilities for analytics.    -   Exposure of analytics to external party.    -   Retrieval of data from external party by NWDAF.

When subscribing to event reporting the Service consumer NF(s) provide:

-   -   One or multiple Event ID(s). An Event ID identifies the type of        event being subscribed to (e.g. PDU Session release, UE mobility        out of an Area of Interest, etc.).    -   Event Filter Information: Provides Event Parameter Types and        Event Parameter Value(s) to be matched against, in order to meet        the condition for notifying the subscribed Event ID e.g. the        Event Parameter Type could be “Area of interest” and Event        Parameter Value list could be list of TAs; The Event Filter        depends on the Event ID. The Event Filter Information is        provided per Event ID(s) being subscribed to: A subscription        different Event ID(s) may be associated with different Event        Filter Information.    -   Event Reporting Information: Within a subscription, all Event        ID(s) are associated with a unique Event Reporting Information.    -   Target of Event Reporting: this may indicate a specific UE or        PDU Session, a group of UE(s) or any UE (i.e. all UEs), Within a        subscription all Event ID (s) are associated with the same        Target of Event Reporting (possibly corresponding to multiple UE        or multiple PDU Sessions).    -   A Notification Target Address (+Notification Correlation ID)        allowing the Event Receiving NF to correlate notifications        received from the Event provider with this subscription. A        subscription is associated with an unique Notification Target        Address (+Notification Correlation ID). In the case that the        Service consumer NF subscribes to the NF producer on behalf of        other NF, the Service consumer NF includes the Notification        Target Address (+Notification Correlation ID) of other NF for        the Event ID which is to be notified to other NF directly, and        the Notification Target Address (+Notification Correlation ID)        of itself for the Subscription change related event        notification. Each Notification Target Address (+Notification        Correlation ID) is associated with related (set of) Event ID(s).    -   An Expiry time represents the time upto which the subscription        is desired to be kept as active. The Service consumer NF may        suggest an Expiry time and provide to the NF service producer.        Based on the operator's policy, the NF service producer decides        whether the subscription may be expired. If the subscription may        be expired, the NF service producer determines the Expiry time        and provide it in the response to the Service consumer NF. If        the event subscription is about to expire based on the received        Expiry time and the Service consumer NF wants to keep receiving        notifications, the Service consumer NF update the subscription        with the NF service producer in order to extend the Expiry time.        Once the Expiry time associated with the subscription is        reached, the subscription becomes invalid at the NF service        producer. If the Service consumer NF wants to keep receiving        notifications, it may create a new subscription with the NF        service producer.

When the subscription is accepted by the Event provider NF, the Serviceconsumer NF receives from the event provider NF an identifier(Subscription Correlation ID) allowing to further manage (modify,delete) this subscription.

The Notification Correlation ID is allocated by the Service consumer NFthat subscribes to event reporting and the Subscription Correlation IDis allocated by the NF that notifies when the event is met. Bothcorrelation identifiers may be assigned the same value, although inprinciple they are supposed to be different, as they are optimized forfinding the subscription related context within each NF.

The Service consumer NF may use an operation dedicated to subscriptionmodification to add or remove Event ID(s) to this subscription or tomodify Event Filter Information.

Events are subscribed by the Service consumer NF(s) by providing EventFilters. The contents of the Event Reporting Information along with thepresence requirement of each information element is described in belowtable 1.

TABLE 1 Event Reporting Information Parameter Description Eventreporting mode Mode of reporting - e.g reporting up to a maximum numberof reports, periodic reporting along with periodicity, reporting up to amaximum duration Maximum number of Maximum number of reports afterreports which the event subscription ceases to exist Maximum duration ofMaximum duration after which the reporting event subscription ceases toexist Immediate reporting The Event provider NF notifies the flagcurrent status of the subscribed event, if available, immediately to theservice consumer NF. Sampling ratio Percentage of sampling (1% . . .100%) among impacted UEs. Group Reporting Parameter for group-basedGuard Time monitoring configuration to indicate the time for which theMonitoring Event Reporting(s) detected by the UEs in a group may beaggregated before sending them to the service consumer NF.

The requester may include 2) Maximum number of reports or 3) Maximumduration of reporting, or both, depending on 1) Event reporting mode.Parameter only is applicable to certain event IDs reporting metrics(e.g. Number of UEs present in a geographical area) and is used e.g. bythe NWDAF for data collection. Explicit unsubscribe by the Serviceconsumer NF is still possible.

Maximum number of reports is applicable to the subscription to one UE ora group of UE(s). When the subscription is applied to a group of UE(s),the parameter is applied to each individual member UE. The count ofnumber of reports is per Event Type granularity.

Maximum duration of reporting is applicable to the subscription to oneUE, a group of UE(s) or any UE. When the subscription is applied to agroup of UE(s), this parameter applies to each group member UE. When thesubscription is applied to any UE, this parameter applies to all theimpacted UEs.

If for a given subscription both Maximum Number of reports and Maximumduration of reporting are included then the subscription is consideredto expire as soon as one of the conditions is met.

Sampling ratio is applicable to subscription targeting a group of UEs orany UE. When a sampling ratio is provided, a random subset is selectedamong the target UEs according to the sampling ratio and only the eventsrelated to this subset are reported. A UE remains selected until it isnot managed by the event provider NF any more. A UE newly managed by theNF may become selected.

Group Reporting Guard Time is an optional parameter for group-basedmonitoring configuration to indicate the time for which the MonitoringEvent Reporting(s) detected by the UEs in a group may be aggregatedbefore sending them to the Service consumer NF. The value of the GroupReporting Guard time should be set less than the Maximum duration ofreporting.

For the continuous monitoring reporting, unless the Maximum duration ofreporting has been reached, the Group Reporting Guard timer is restartedwhen it expires. If the time left until the Maximum duration ofreporting is less than the Group Reporting Guard Time, then the GroupReporting Guard timer may be set to expire when the Maximum duration ofreporting expires. If the Maximum duration of reporting is expired, theGroup Reporting Guard Time, if running, may be considered to expire andaggregated Monitoring Event Reporting(s) is sent to destinationimmediately.

Corresponding notifications contain at least the NotificationCorrelation ID together with the Event ID and the individual target(e.g. UE or PDU Session ID) associated with the notification.

If the Service consumer NF decides to terminate the event subscription,it unsubscribes the event subscription by sending unsubscription requestto the event provider NF. After receiving unsubscription request fromthe Service consumer NF, the event provider NF terminates the eventsubscription.

The external exposure of network capabilities and core network internalevent and capability exposure is described. When the immediate reportingflag is set, the first corresponding event report is included in theoutput message, if corresponding information is available at thereception of the subscription request of the event.

The optional parameter MTC Provider Information is a reference parameterthat may be provided by AF or determined by NEF based on which AF itcommunicates with. The MTC Provider Information identifies the MTCService Provider and/or MTC Application. The MTC Provider Informationmay be used by Service Providers for, e.g. to distinguish theirdifferent customers.

<External Exposure of Network Capabilities>

The Network Exposure Function (NEF) supports external exposure ofcapabilities of network functions. External exposure may be categorizedas Monitoring capability, Provisioning capability, Policy/Chargingcapability, network status reporting capability and Analytics reportingcapability. The Monitoring capability is for monitoring of specificevent for UE in 5GS and making such monitoring events informationavailable for external exposure via the NEF. The Provisioning capabilityis for allowing external party to provision of information which may beused for the UE in 5GS. The Policy/Charging capability is for handlingQoS and charging policy for the UE based on the request from externalparty. The Analytics capability is for allowing external party toacquire analytics information generated by 5G System. The details forthe External Exposure of Analytics capabilities as well as interactionsbetween NEF, external party and NWDAF are described.

<Data Collection from an AF>

The Network Exposure Function (NEF) supports the capability to collectdata from an AR

<Network Function Service Procedures>

Network Function Service framework procedures

Network Function Service Discovery

The network function (NF) within the core network may expose itscapability as service via its service based interfaces, which may bere-used by other NFs. Unless the expected NF information is locallyconfigured on requester NF, e.g. the expected NF is in the same PLMN,the NF service discovery is implemented via the NF discovery.

<External Exposure of Network Capability>

The Network Exposure Function (NEF) supports external exposure ofcapabilities of network functions. External exposure may be categorizedas Monitoring capability, Provisioning capability, Policy/Chargingcapability and Analytics reporting capability. The Monitoring capabilityis for monitoring of specific event for UE in 5G System and making suchmonitoring events information available for external exposure via theNEF. The Provisioning capability is for allowing external party toprovision of information which may be used for the UE in 5G System. ThePolicy/Charging capability is for handling QoS and charging policy forthe UE based on the request from external party. The Analytics reportingcapability is for allowing an external party to fetch orsubscribe/unsubscribe to analytics information generated by 5G System.

Monitoring capability is comprised of means that allow theidentification of the 5G network function suitable for configuring thespecific monitoring events, detect the monitoring event, and report themonitoring event to the authorised external party. Monitoring capabilitymay be used for exposing UE's mobility management context such as UElocation, reachability, roaming status, and loss of connectivity. AMFstores URRP-AMF information in the MM context to determine the NFs thatare authorised to receive direct notifications from the AMF. UDM storesURRP-AMF information locally to determine authorised monitoring requestswhen forwarding indirect notifications.

Provisioning capability allows an external party to provision theExpected UE Behaviour or the 5GLAN group information or service specificinformation to 5G NF via the NEF. The provisioning comprises of theauthorisation of the provisioning external third party, receiving theprovisioned external information via the NEF, storing the provisionedexternal information, and distributing that provisioned externalinformation among those NFs that use provisioned external information.The externally provisioned data may be consumed by different NFs,depending on the data. In the case of provisioning the Expected UEBehaviour, the externally provisioned information which is defined asthe Expected UE Behaviour parameters or Network Control parameterconsists of information on expected UE movement, Expected UE Behaviourparameters or expected Network Configuration parameter.

The provisioned Expected UE Behaviour parameters may be used for thesetting of mobility management or session management parameters of theUE. In the case of provisioning the 5GLAN group information, theexternally provisioned information is defined as the 5GLAN groupparameters, and the externally provisioned information consists of someinformation on the 5GLAN group. The affected NFs are informed via thesubscriber data update. The externally provisioned information which isdefined as the Service Parameters consists of service specificinformation used for supporting the specific service in 5G system. Theprovisioned Service Parameters may be delivered to the UEs. The affectedNFs are informed of the data update.

Policy/Charging capability is comprised of means that allow the requestfor session and charging policy, enforce QoS policy, and applyaccounting functionality. It may be used for specific QoS/priorityhandling for the session of the UE, and for setting applicable chargingparty or charging rate.

Analytics reporting capability is comprised of means that allowdiscovery of type of analytics that may be consumed by external party,the request for consumption of analytics information generated by NWDAF.

An NEF may support CAPIF functions for external exposure as specified.

An NEF may support exposure of NWDAF analytics as specified.

<Data Collection from an AF>

An NF that needs to collect data from an AF may subscribe/unsubscribe tonotifications regarding data collected from an AF, either directly fromthe AF or via NEF.

The data collected from an AF is used as input for analytics by theNWDAF.

The details for the data collected from an AF as well as interactionsbetween NEF, AF and NWDAF are described.

Hereinafter, the service operation described in the present inventionwill be described in detail.

<NEF Services>

*Nnef_EventExposure service

(1) Nnef_EventExposure_Subscribe Operation

Service operation name: Nnef_EventExposure_Subscribe

Description: the service consumer NF subscribes to receive an event, orif the event is already defined in NEF, then the subscription isupdated.

Inputs (required): (Set of) Event ID(s) orNpcf_PolicyAuthorization_Notify and Naf_EventExposure_Subscribe serviceoperation, Target of Event Reporting (GPSI or External GroupIdentifier), Event Reporting Information, Notification Target Address(+Notification Correlation ID).

Inputs (optional): Event Filter, Subscription Correlation ID (in case ofmodification of the event subscription), Expiry time.

Outputs (required): When the subscription is accepted: SubscriptionCorrelation ID, Expiry time (required if the subscription may be expiredbased on the operator's policy).

Outputs (optional): First corresponding event report is included, ifavailable.

(2) Nnef_EventExposure_Unsubscribe Service Operation

Service operation name: Nnef_EventExposure_Unsubscribe

Description: the Service consumer NF deletes an event if already definedin NEF.

Inputs (required): Subscription Correlation ID.

Outputs (required): Operation execution result indication.

(3) Nnef_EventExposure_Notify Service Operation

Service operation name: Nnef_EventExposure_Notify

Description: NEF reports the event to the service consumer NF that haspreviously subscribed.

Inputs (required): Event ID, Notification Correlation Information, timestamp.

Inputs (optional): Event information (defined on a per Event ID basis).

Outputs (required): Operation execution result indication.

<Af Services>

*Naf_EventExposure service

Service description: This service enables service consumer NF tosubscribe and get notified of events.

The events may be subscribed by a Service consumer NF are described.

The following service operations are defined for the Naf_EventExposureservice:

-   -   Naf_EventExposure_Subscribe.    -   Naf_EventExposure_Unsubscribe.    -   Naf_EventExposure_Notify.

(1) Naf_EventExposure_Subscribe Service Operation

Service operation name: Naf_EventExposure_Subscribe

Description: The service consumer NF subscribes the event to collect AFdata for UE(s), group of UEs, or any UE, or updates the subscriptionwhich is already defined in AF.

Input, Required: Target of Event Reporting: external UE ID(s), ExternalGroup Identifier, or indication that any UE is targeted, (set of) EventID(s), Notification Target Address (+Notification Correlation ID) andEvent Reporting Information, Expiry time.

Input, Optional: NF ID, Event Filter(s) associated with each Event ID,Application ID, Subscription Correlation ID (in case of modification ofthe existing subscription).

NOTE: In the case of untrusted AF, NEF ID is used as NF ID.

Output, Required: Operation execution result indication. When thesubscription is accepted: Subscription Correlation ID.

Output, Optional: First corresponding event report is included, ifcorresponding information is available.

(2) Naf_EventExposure_Unsubscribe Service Operation

Service operation name: Naf_EventExposure_Unsubscribe

Description: The service consumer NF unsubscribes for a specific event.

Input, Required: Subscription Correlation ID.

Input, Optional: None.

Output, Required: Operation execution result indication.

Output, Optional: None.

(3) Naf_EventExposure_Notify Service Operation

Service operation name: Naf_EventExposure_Notify

Description: The AF provides the previously subscribed event informationto the service consumer NF which has subscribed to that event before.

Input, Required: Notification Correlation Information, Event ID,corresponding UE(s) (external UE ID(s), External Group Identifier, orindication of any UE), time stamp.

Input, Optional: Event specific parameter list.

Output, Required: None.

Output, Optional: None.

<Namf_EventExposure Service>

*Namf_EventExposure_Subscribe service operation

Service operation name: Namf_EventExposure_Subscribe.

Description: The service consumer NF uses this service operation tosubscribe to or modify event reporting for one UE, a group of UE(s) orany UE.

Input, Required: NF ID, Target of Event Reporting: UE(s) ID (SUPI orInternal Group Identifier or indication that any UE is targeted), ((setof) Event ID(s), Notification Target Address (+Notification CorrelationID))s, Event Reporting Information.

Input, Optional: (Event Filter (s) associated with each Event ID; EventFilter (s), Subscription Correlation ID (in the case of modification ofthe event subscription), Expiry time.

Output, Required: When the subscription is accepted: SubscriptionCorrelation ID (required for management of this subscription), Expirytime (required if the subscription may be expired based on theoperator's policy).

Output, Optional: First corresponding event report is included, ifavailable.

The Service consumer NF subscribes to the event notification by invokingNamf_EventExposure to the AMF. The AMF allocates an SubscriptionCorrelation ID for the subscription and responds to the service consumerNF with the Subscription Correlation ID. UE ID identifies the UE, SUPIand/or GPSI. Event ID identifies the events that the Service consumer NFis interested in. The Subscription Correlation ID is unique within theAMF Set.

The ((set of) Event ID(s), Notification Target Address (+NotificationCorrelation ID)) helps the Event Receiving NF to co-relate anotification against a corresponding event subscription for theindicated Event ID.

In the case that the Service consumer NF subscribes to the AMF on behalfof other NF, the Service consumer NF include the Notification TargetAddress (+Notification Correlation ID) of other NF for the Event IDwhich is to be notified to other NF directly, and the NotificationTarget Address (+Notification Correlation ID) of itself for theSubscription Correlation ID change event. Each Notification TargetAddress (+Notification Correlation ID) is associated with the related(set of) Event ID(s). When the Subscription Correlation ID change due tothe AMF reallocation, the notification is sent to Service consumer NFwhich triggers this subscription.

Event filter may include “AN type(s)” as part of the list of parametervalues to match, and it indicates to subscribe the event per AccessType. Event receiving NF ID identifies the NF that may receive the eventreporting. When the service consumer NF needs to modify an existingsubscription previously created by itself in the AMF, the serviceconsumer NF invokes Namf_EventExposure_Subscribe service operation whichcontains the Subscription Correlation ID and the new Event Filters withEvent ID to the AME

<Nudm_EventExposure_Subscribe Service Operation>

Service operation name: Nudm_EventExposure_Subscribe

Description: The Service consumer NF subscribes to receive an event, orif the subscription is already defined in UDM, then the subscription isupdated.

Service consumer NFs: NEF.

Inputs (required): Target of Event Reporting: UE(s) ID (SUPI or GPSI,Internal Group Identifier or External Group Identifier, or indicationthat any UE is targeted), Event filter containing the Event Id(s) andEvent Reporting Information.

Inputs (optional): Expiry time.

Outputs (required): Operation execution result indication. When thesubscription is accepted: Subscription Correlation ID, Expiry time(required if the subscription may be expired based on the operator'spolicy).

Outputs (optional): First corresponding event report is included, ifcorresponding information is available, Number of UE if the ExternalGroup Identifier and Maximum Number of Reports are included in theinputs.

Number of UEs indicates the number of UEs within the group identified bythe External Group Identifier. The NEF uses this value to determinewhether the monitoring event has been reported for all group member UEs.

<Npcf_EventExposure_Subscribe Service Operation>

Service operation name: Npcf_EventExposure_Subscribe.

Description: The service consumer NF uses this service operation tosubscribe to or modify event reporting for a group of UE(s) or any UEaccessing a combination of (DNN, S-NSSAI).

Service consumer NFs: NEF.

Inputs (required): NF ID, Target of Event Reporting (Internal GroupIdentifier or indication that any UE accessing a combination of (DNN,S-NSSAI) is targeted, (set of) Event ID(s), Notification Target Address(+Notification Correlation ID) and Event Reporting Information.

Inputs (optional): Event Filter (s) associated with each Event ID.

Outputs (required): Operation execution result indication. When thesubscription is accepted: Subscription Correlation ID.

Outputs (optional): First corresponding event report is included, ifcorresponding information is available.

The Service consumer NF subscribes to the event notification by invokingNpcf_EventExposure to the PCF. The PCF allocates a SubscriptionCorrelation ID for the subscription and responds to the service consumerNF with the Subscription Correlation ID. Event receiving NF IDidentifies the NF that may receive the event reporting.

<Nsmf_EventExposure_Subscribe Service Operation>

Service operation name: Nsmf_EventExposure_Subscribe.

Description: This service operation is used by an NF to subscribe ormodify a subscription for event notifications on a specified PDU Sessionor for all PDU Sessions of one UE, group of UE(s) or any UE.

Input, Required: NF ID, Target of Event Reporting, (set of) Event ID(s),Notification Target Address (+Notification Correlation ID), EventReporting Information.

Input, Optional: Event Filter(s) associated with each Event ID; EventFilter(s) are defined, Subscription Correlation ID (in case ofmodification of the event subscription), Expiry time.

Output, Required: When the subscription is accepted: SubscriptionCorrelation ID (required for management of this subscription), Expirytime (required if the subscription may be expired based on the operatorspolicy).

Output, Optional: First corresponding event report is included, ifavailable.

Notification Target Address (+Notification Correlation ID) is used tocorrelate Notifications sent by SMF with this subscription.

<Procedures for Data Collection>

The Data Collection feature permits NWDAF to retrieve data from varioussources (e.g. NF such as AMF, SMF, PCF, AF), as a basis of thecomputation of network analytics.

All available data encompass:

-   -   OAM global NF data,    -   behaviour data related to individual UEs or UE groups (e.g. UE        reachability), and pre-computed metrics covering UE populations        (e.g. number of UEs present in a geographical area), per spatial        and temporal dimensions (e.g. per region for a period of time),    -   NF data available in the 5GC (e.g. NRF),    -   Data available in AF.

The NWDAF may use at least one of the following services:

-   -   the Generic management services offered by OAM in order to        collect OAM global NF data.    -   the Exposure services offered by NFs in order to retrieve NF        data and other non-OAM pre-computed metrics.    -   Other NF services in order to collect NF data (e.g. NRF)

The NWDAF may obtain the proper information to perform data collectionfor a UE or group of UEs:

-   -   For an Analytics ID, NWDAF is configured with the corresponding        NF Type(s) and/or event ID(s) and/or OAM measurement types.    -   NWDAF may determine which NF instance(s) of the relevant NF        type(s) are serving the UE or group of UEs, optionally taking        into account the S-NSSAI(s) and area of interest.    -   NWDAF invokes Nnf_EventSubscribe services to collect data from        the determined NF instance(s), and/or triggers the procedure to        subscribe to OAM services to collect the OAM measurement.

The NWDAF performs data collection from an AF directly as defined or viaNEF as defined. The NWDAF may be able to discover the metrics supportedby a NF. Data collection procedures enables the NWDAF to efficientlyobtain the appropriate data with the appropriate granularity. When arequest or subscription for statistics or predictions is received, theNWDAF may not possess the necessary data to perform the service.

-   -   Data on the monitoring period in the past matching the Analytics        target period is necessary for the provision of statistics and        predictions.    -   Data on longer monitoring periods in the past is necessary for        model training.

Therefore, in order to optimize the service quality, the NWDAF mayundertake the following actions:

-   -   The NWDAF may return a probability assertion expressing the        confidence in the analytics produced. With zero confidence, no        analytics may be returned. This confidence is likely to grow in        the case of subscriptions.    -   The value of the confidence depends on the level or urgency        expressed by the parameter “time when analytics information is        needed” as listed, the parameter “preferred level of accuracy of        the analytics” as listed, the availability of data. If no        sufficient data is collected to provide an estimation for the        requested level of accuracy before the time deadline, the        service may return a zero confidence. Otherwise, the NWDAF may        wait until enough data is collected before providing a response        or a first notification.    -   In order to be prepared for future requests on statistics from        NFs/OAM, the NWDAF, upon operator configuration, may collect        data on its own initiative, e.g. on samples of UEs (e.g.        mobility), and retain the data collected in the data storage.

The volume and maximum duration of data storage is also subject ofoperator configuration. The NWDAF may decide to reduce the amount ofdata collection in case of high signalling load, by either prioritizingrequests, reducing the duration of data collection, or the samplingratios. The NWDAF may skip data collection phase when the NWDAF alreadyhas enough information to provide requested analytics.

The data which NWDAF may collect is listed for each analytics in inputdata clause. NWDAF may skip data collection phase for some specificinput data per the requested analytics e.g. when some of the data isalready available at NWDAF for the requested analytics, or when NWDAFconsiders that some of the data is not needed at all to provide therequested analytics as per the analytics consumer request (e.g. based onpreferred level of accuracy or based on the time when analytics areneeded).

<Data Collection from NFs>

The Data Collection from NFs is used by NWDAF to subscribe/unsubscribeat any NF to be notified for data on a set of events. The DataCollection from NFs is based on the services of AMF, SMF, UDM, PCF, NRFand AF (possibly via NEF):

-   -   Event Exposure Service offered by each NF.    -   other NF services (e.g. Nnrf_NFDiscovery and Nnrf_NFManagement        in NRF)

This data collection service is used directly in order to retrievebehaviour data for individual UEs or groups of UEs (e.g. UEreachability), and also to retrieve global UE information (e.g. Numberof UEs present in a geographical area).

To retrieve data related to a specific UE, the NWDAF may first determinewhich NF instances are serving this UE unless the NWDAF has alreadyobtained this information due to recent operations related to this UE.

Table 2 shows the services consumed by the NWDAF device for datacollection.

TABLE 2 Service producer Service AMF Namf_EventExposure SMFNsmf_EventExposure PCF Npcf_EventExposure UDM Nudm_EventExposure NEFNnef_EventExposure AF Naf_EventExposure NRF Nnrf_NFDiscoveryNnrf_NFManagement

Table 3 shows NF services consumed by an NWDAF device that determineswhether to provide an NF instance to a user terminal.

TABLE 3 NF instance (serving the UE) NF to be contacted to determine byNWDAF Service UDM NRF Nnrf_NFDiscovery AMF UDM Nudm_UECM SMF UDMNudm_UECM BSF NRF Nnrf_NFDiscovery PCF BSF Nbsf_Management NEF FFS AFFFS

The AMF, SMF instances should be determined using a request to UDMproviding the SUPI. To determine the SMF serving a PDU session, theNWDAF should in addition provide the DNN and S-NSSAI of this PDUSession; otherwise the NWDAF will obtain a list of possibly multipleSMFs (e.g. one per PDU session). The BSF instance should be discoveredusing NRF thanks to optional request parameters (e.g. DNN list, IPdomain list, IPv4 address range, IPv6 prefix range), or based on localconfiguration at the NWDAF. The PCF instance serving UE PDU Session(s)should be determined using a request to BSF with the SUPI. To determinethe PCF serving a PDU session, the NWDAF should in addition provide theDNN and S-NSSAI of this PDU Session; otherwise the NWDAF will obtain alist of possibly multiple PCFs (e.g. one per PDU session).

FIG. 2 is a diagram illustrating a procedure for collecting data from NFdevice according to an example embodiment.

The procedure is used by NWDAF to subscribe/unsubscribe at NFs in orderto be notified for data collection on a related event (s), using EventExposure Services

1. The NWDAF subscribes to or maycels subscription for a (set of) EventID(s) by invoking theNnf_EventExposure_Subscribe/Nnf_EventExposure_Unsubscribe serviceoperation.

2. If NWDAF subscribes to a (set of) Event ID(s), the NFs notify theNWDAF (e.g. with the event report) by invoking Nnf_EventExposure_Notifyservice operation.

The NWDAF may use the immediate reporting flag to meet therequest-response model for data collection from NFs.

FIG. 3 is a flowchart illustrating a procedure for collecting data fromAF device via NEF device according to an example embodiment.

The procedure is used by NWDAF to collect information from AFs via theNEF. In this release, AF registers its available data to NWDAF via OAMconfiguration at NEF. The AF collectable data information includes: AFidentification, AF service identification (e.g., endpoint information ofNaf_EventExposure), available data to be collected per application(e.g., identified by Event ID(s)).

1a. After the registration of AF available data at the NEF, NEFgenerates an event exposure with new EventID to be associated withavailable data to be collected from AR NEF invokesNnrf_NFManagement_NFUpdate_request service operation to update itsregistration information (i.e., NEF Profile) including the generatedEvent IDs, and associated AF identification, Application ID(s).

1b. NRF stores the received NEF registration information includingavailable data to be collected from AF.

1c. NRF sends Nnrf_NFManagement_NFUpdate_response message to NEF.

1d. When NWDAF needs to discovery the available data from AFs and theappropriated NEF to collect this data, NWDAF invokesNnrf_NFDiscovery_Request_request service operation using as parameterincluding the NEF NF Type, a list of Event ID(s), and optionally AFidentification, application ID.

1e. NRF matches the requested query for available data in AFs with theregistered NEF Profiles and sends this information viaNnrf_NFDiscovery_Request_response message to NWDAF. After theregistration and discovery procedure, NWDAF identifies the availabledata per AF per application and the proper NEF to collect such data.

2. The NWDAF subscribes to or maycels subscription to data in AF via NEFby invoking the Nnef_EventExposure_Subscribe orNnef_EventExposure_Unsubscribe service operation. If the eventsubscription is authorized by the NEF, the NEF records the associationof the event trigger and the NWDAF identity.

3. Based on the request from the NWDAF, the NEF subscribes to or maycelssubscription to data in AF by invoking theNaf_EventExposure_Subscribe/Naf_EventExposure_Unsubscribe serviceoperation.

4. If the NEF subscribes to data in AF, the AF notifies the NEF with thedata by invoking Naf_EventExposure_Notify service operation.

5. If the NEF receives the notification from the AF, the NEF notifiesthe NWDAF with the data by invoking Nnef_EventExposure_Notify serviceoperation. The NWDAF may use NRF services and Network Function serviceframework procedures:

<Data Collection from the NRF>

-   -   NF/NF service discovery procedures and Nnrf_NFDiscovery is used        in order to dynamically discover the NF instances and services        of the 5GC. Such discovery may be performed on a periodic basis,        or under specific circumstances.    -   NF/NF service status subscribe/notify procedures and        Nnrf_NFManagement service is used in order to be notified about        the change of status of an NF. The service operations for        obtaining status information are NFStatusSubscribe and        NFStatusNotify, from the Nnrf_NFManagement service.

The information provided by the NRF to the NWDAF with theNnrf_NFDiscovery_Request and the Nnrf_NFManagement_NFStatusNotifyoperations are the NFProfile and the NFService. Such information may beused to set-up and maintain a consistent network map for data collectionand also, depending on use cases, in order to perform estimations:

-   -   NF profile: NF capacity, NF load information, NF status, NF        recovery time, NF locality;    -   NF service: service capacity, service load information, service        status, service recovery time.    -   NF Profile: NF capacity, NF load information, NF status, NF        recovery time, NF locality    -   NF service: service capacity, service load information, service        status, service recovery time

<Usage of Exposure framework by the NWDAF for Data Collection>

The NWDAF may subscribe (and unsubscribe) to the Event exposure servicefrom NF(s) reusing the framework. This framework supports thepossibility for the NWDAF to indicate/request:

-   -   Events-ID: one or multiple Event ID(s)    -   Target of Event Reporting: the objects targeted by the Events.        Within a subscription, all Event ID(s) are associated with the        same target of event reporting. In the case of NWDAF, the        objects may be UE(s), UE group(s), any UE.    -   Event Filter Information. This provides Event Parameter Types        and Event Parameter Value(s) to be matched against.    -   A Notification Target Address and a Notification Correlation ID,        allowing the NWDAF to correlate notifications received from the        NF with this subscription.    -   Event Reporting Information.    -   Expiry time.

The notifications from NFs/AFs contain on top of the Event beingreported (and of dedicated information being reported for this event):

-   -   the Notification Correlation Information provided by the NWDAF        in its request,    -   (when applicable to the event) the Target Id e.g. UE ID (SUPI        and if available GPSI), and    -   a time stamp.

FIG. 4 is a flowchart illustrating a procedure for collecting data fromOAM device according to an example embodiment.

The NWDAF may collect relevant management data from the services in theOAM as configured by the PLMN operator.

-   -   NG RAN or 5GC performance measurements.    -   5G End to end KPIs.    -   NG RAN        5GC performance measurements    -   5G End to end KPIs

NWDAF may use the following services to have access to the informationprovided by OAM:

-   -   Generic performance assurance and fault supervision management        services.    -   PM (Performance Management) services.    -   FS (Fault Supervision) services.

OAM perform the required configuration in order to provide theinformation requested by NWDAF subscription and perform the tasks, e.g.data collection, data processing, associated with the subscribed requestfrom NWDAF.

The interactions between NWDAF and OAM for data collection areillustrated. The data collected depends on the use cases. The flow belowassumes the NWDAF is configured on how to subscribe to the relevant OAMservices. OAM may setup the required mechanisms to guarantee thecontinuous data collection requested by NWDAF.

1. Subscribe (Input): NWDAF subscribes to the notification(s) related tothe services provided by the management service producer.

2. Subscribe (Output): management service producer responses to NWDAF ifthe subscription is success or not.

3. Data processing: management service producer prepares the data.

4. Notification (notifyFileReady): management service producer notifiesthe data file is ready. As the final step, NWDAF fetches data by usingFTP.

The components described in the example embodiments may be implementedby hardware components including, for example, at least one digitalsignal processor (DSP), a processor, a controller, anapplication-specific integrated circuit (ASIC), a programmable logicelement, such as a field programmable gate array (FPGA), otherelectronic devices, or combinations thereof. At least some of thefunctions or the processes described in the example embodiments may beimplemented by software, and the software may be recorded on a recordingmedium. The components, the functions, and the processes described inthe example embodiments may be implemented by a combination of hardwareand software.

The apparatus described herein may be implemented using a hardwarecomponent, a software component and/or a combination thereof. Aprocessing device may be implemented using one or more general-purposeor special purpose computers, such as, for example, a processor, acontroller and an arithmetic logic unit (ALU), a DSP, a microcomputer,an FPGA, a programmable logic unit (PLU), a microprocessor or any otherdevice capable of responding to and executing instructions in a definedmanner. The processing device may run an operating system (OS) and oneor more software applications that run on the OS. The processing devicealso may access, store, manipulate, process, and create data in responseto execution of the software. For purpose of simplicity, the descriptionof a processing device is used as singular; however, one skilled in theart will appreciated that a processing device may include multipleprocessing elements and multiple types of processing elements. Forexample, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are possible, such a parallel processors.

The software may include a computer program, a piece of code, aninstruction, or some combination thereof, to independently orcollectively instruct or configure the processing device to operate asdesired. Software and data may be embodied permanently or temporarily inany type of machine, component, physical or virtual equipment, computerstorage medium or device, or in a propagated signal wave capable ofproviding instructions or data to or being interpreted by the processingdevice. The software also may be distributed over network coupledcomputer systems so that the software is stored and executed in adistributed fashion. The software and data may be stored by one or morenon-transitory computer readable recording mediums.

The methods according to the above-described example embodiments may berecorded in non-transitory computer-readable media including programinstructions to implement various operations of the above-describedexample embodiments. The media may also include, alone or in combinationwith the program instructions, data files, data structures, and thelike. The program instructions recorded on the media may be thosespecially designed and constructed for the purposes of exampleembodiments, or they may be of the kind well-known and available tothose having skill in the computer software arts. Examples ofnon-transitory computer-readable media include magnetic media such ashard disks, floppy disks, and magnetic tape; optical media such asCD-ROM discs, DVDs, and/or Blue-ray discs; magneto-optical media such asoptical discs; and hardware devices that are specially configured tostore and perform program instructions, such as read-only memory (ROM),random access memory (RAM), flash memory (e.g., USB flash drives, memorycards, memory sticks, etc.), and the like. Examples of programinstructions include both machine code, such as produced by a compiler,and files containing higher level code that may be executed by thecomputer using an interpreter. The above-described devices may beconfigured to act as one or more software modules in order to performthe operations of the above-described example embodiments, or viceversa.

A number of example embodiments have been described above. Nevertheless,it should be understood that various modifications may be made to theseexample embodiments. For example, suitable results may be achieved ifthe described techniques are performed in a different order and/or ifcomponents in a described system, architecture, device, or circuit arecombined in a different manner and/or replaced or supplemented by othercomponents or their equivalents. Accordingly, other implementations arewithin the scope of the following claims.

What is claimed is:
 1. A network data collecting method performed by anetwork exposure function (NEF) device, comprising: transmitting aNnrf_NFManagement_NFUpdate_request message for update registrationinformation into a network repository function (NRF) device; receiving aNnrf_NFManagement_NFUpdate_response message from the NRF device;receiving a Nnef_EventExposure_Subscribe message from a network dataanalytic function (NWDAF) device; transmitting aNaf_EventExposure_Subscribe message into an application function (AF)device; receiving a Naf_EventExposure_Notify message from the AF device;transmitting a Nnef_EventExposure_Notify message into the NWDAF device,wherein the Naf_EventExposure_Subscribe message comprise: (i) an inputincluding a Target of Event Reporting, external UE ID, External GroupIdentifier, indication that any UE is targeted, an Event ID, aNotification Target Address with Notification Correlation ID), EventReporting Information and an Expiry time, (ii) an output including anOperation execution result indication, and a Subscription CorrelationID, when the subscription is accepted.
 2. The method of claim 1, whereinthe NRF device stores NEF registration information including availabledata to be collected from the AF device.
 3. The method of claim 1,wherein the Nnef_EventExposure_Subscribe message comprise: (i) an inputincluding an Event ID, a Target of Event Reporting, a GPSI, a ExternalGroup Identifier, Event Reporting Information, or a Notification TargetAddress with Notification Correlation ID, and (ii) an output including aSubscription Correlation ID, or Expiry time.
 4. The method of claim 1,further comprising: transmitting a Naf_EventExposure_Unsubscribe messageinto the AF device, wherein the Naf_EventExposure_Unsubscribe comprises:(i) an input including a Subscription Correlation ID, and (ii) an outputincluding an Operation execution result indication.
 5. The method ofclaim 1, wherein the Naf_EventExposure_Notify message comprises: (i) aninput including Notification Correlation Information, an Event ID,corresponding UE external UE ID, an External Group Identifier, anindication of any UE or time stamp.
 6. The method of claim 1, whereinthe Nnef_EventExposure_Notify message comprises: (i) an input includingan Event ID, Notification Correlation Information or time stamp, and(ii) an output including an Operation execution result indication. 7.The method of claim 1, wherein the AF device invokes theNaf_EventExposure_Notify message into the NEF device, when the NEFdevice subscribes to data in the AF device.
 8. The method of claim 1,wherein the NEF device invokes the Nnef_EventExposure_Notify messageinto the NWDAF device, when the NEF device receives a notification fromthe AF device.
 9. The method of claim 1, wherein the NWDAF deviceinvokes the Nnrf_NFDiscovery_Request_request message, when the NWDAFneeds to discovery an available data from the AF device and theappropriated NEF device to collect the available data.
 10. A networkdata collecting method performed by a network data analytic function(NWDAF) device, comprising: transmitting a Naf_EventExposure_Subscribemessage for a subscription of an event into an application function (AF)device; and receiving a Naf_EventExposure_Notify message from the AFdevice when the NWDAF subscribes the event, wherein theNaf_EventExposure_Subscribe message comprises: (i) an input including aTarget of Event Reporting, an external UE ID, External Group Identifier,an indication that any UE is targeted, an Event ID, a NotificationTarget Address with Notification Correlation ID), an Event ReportingInformation and Expiry time, (ii) an output including a Operationexecution result indication, and a Subscription Correlation ID, when thesubscription is accepted.
 11. The method of claim 10, wherein theNaf_EventExposure_Notify message comprises: (i) an input includingNotification Correlation Information, an Event ID, corresponding UEexternal UE ID, an External Group Identifier, an indication of any UE ortime stamp.
 12. The method of claim 10, further comprising: transmittinga Naf_EventExposure_Unsubscribe message into the AF device, wherein theNaf_EventExposure_Unsubscribe comprises: (i) an input including aSubscription Correlation ID, and (ii) an output including an Operationexecution result indication.